Carbon black production

ABSTRACT

Process for the production of carbon black by the pyrolytic decomposition of a hydrocarbon feed in a reactor having an axial zone, a combustion zone, and a carbon black formation zone in axial alignment wherein the gases in the axial zone are passed through a cone and/or choke and into the combustion zone and a portion of the gases downstream of the choke passed to the upstream side of the choke.

United States Patent Inventors Eulas W. Henderson Bartlesvllle, 0kla.;Glenn J. Forseth, Phillips. Tex. Appl. No. 769,281 Filed Oct. 21, I968Patented Nov. 9, 1971 Assignee Phillips Petroleum Company CARBON BLACKPRODUCTION 6 Claims, 2 Drawing Figs.

US. Cl

Int. Cl Field of Search [56] References Cited UNITED STATES PATENTS2,769,692 1 1/1956 Hellerm... 23/2094 2,865,717 l2/l958 Krejci 23/209.43.256.065 6/1966 Latham 23/259.5 3,333,928 8/1967 Kobayashi 23/20963,355,247 11/1967 Krejci et al1 23/209.4 3,486,853 12/1969 Henderson eta] 23/2096 Primary Examiner- Edward J. Meros Atmrney- Young and QuiggABSTRACT: Process for the production of carbon black by the pyrolyticdecomposition of a hydrocarbon feed in a reactor having an axial zone, acombustion zone. and a carbon black formation zone in axial alignmentwherein the gases in the axial zone are passed through a cone and/0rchoke and into the combustion zone and a portion of the gases downstreamof the choke passed to the upstream side of the choke.

PATENTEDmJv sum 3.619.141

INVENTORS E.W. HENDERSON BY G. J. FORSETH A T TORNE VS CARBON BLACKPRODUCTION This invention relates to a process and to equipment forproducing carbon black.

In one of its more specific aspects, this invention relates to processand related equipment for increasing the variety of blacks which can beproduced in a single reactor.

Most carbon black reactors are limited as to the variety of blacks whichthey can produce. Generally, a reactor of a certain size andconfiguration is used to produce a limited number of blacks and certainqualities, while a reactor of a different size and configuration is usedto produce blacks of other qualities.

It has now been determined that the product quality range for any axialreactor can be considerably extended by the use of a particular choke inthe axial zone. By product property range is meant the variety of carbonblack having different property ranges. The wider the range of carbonblack varieties producible in any one reactor, the fewer the reactorswhich will be required in order to produce the multitude of commerciallyimportant carbon blacks.

According to this invention, there is provided a carbon black reactorcomprising a plurality of axially contiguous zones, there beingpositioned in the first of these zones a choke, the outer wall of whichis positioned in peripheral contact with the inner wall of a reactionzone, the choke having a longitudinal bore, and being otherwise adaptedto provide open communication between that portion of the reactordownwstream of the choke and that portion of the reactor upstream of thechoke.

In one embodiment of this invention, the choke is adapted to receiveinto the upstream end of its bore a truncated cone, the cone beingadapted for the projection of the make-oil injection nozzletherethrough.

Also, in accordance with this invention, there is provided a process forthe production of carbon black which comprises passing a first reactantmass at accelerated velocity through at least one portion of a firstreaction zone, passing the first reactant mass into a second zone,commingling the first reactant mass with a second reactant mass in thesecond reaction zone to form a commingled reaction mass and passing aportion of the commingled reaction mass into the first reaction zone andpassing-a portion of the commingled reaction mass into a third reactionzone from which carbon black is recovered.

Accordingly, it is an object of this invention to provide an improvedcarbon black reactor.

It is another object of this invention to provide an improved processfor the production of carbon black.

These, and other objects of this invention will be more easilyunderstood by referring to the attached drawings in which FIG. 1 is aview in elevation of one embodiment of this invention and F IG. 2 is asectional view through 2-2 of FIG. 1;

Referring now to FIG. 1, there is shown a carbon black reactor havingaxially contiguous zones 1, 2 and 3.

Zone 1 is the axial or feed introduction zone; zone 2 is a combustionzone; zone 3 is a carbon black formation zone from which the carbonblack is recovered through outlet conduit 5.

Axial zone 1 is adapted with make oil inlet conduit 6 equipped withoutlet nozzle 8. Outlet nozzle 8 is positionable at any place along theaxial length of zone l by adjusting conduit 6 through packing gland 7.

ln open communication with axial zone 1 is conduit 9, through whichaxial air is introduced, and conduit 10 through which a fuel can beintroduced.

Combustion zone 2 is adapted with one or more entry ports 11 throughwhich quantities of air, fuel, or make-oil, or any combination thereof,can be introduced to form a mass of hot combustion gas which enters thereaction zone in enveloping relation to the mass of reactants formedwithin zone 1.

Zone 3, the carbon black producing zone, is generally considered as thezone in which a principal portion of the carbon black is formed and fromwhich the carbon black is removed from the reactor.

Axial zone 1 may be considered as extending to upstream wall 12 of zone2. Zone 1 is preferably of circular configuration being enclosed by wall16.

Variably positionable along the longitudinal axis of zone 1 is cone 20which can be supported from make oil inlet conduit 6, or which can beseparately supported on support 26, as shown. Cone 20 is a hollow, opencone such that reactants introduced into zone 1 flow into the base 24 ofthe cone, and out through truncated opening 23. While the passagewaythrough cone 20 is shown as conical, the passageway can be of any shape,but preferably it is of decreasing diameter in the direction of fluidflow through the cone.

Cone 20 can be of any length and of any diameter. It is preferable,however, that the diameter of its upstream base 24 be about it inch toabout 3 inches less than the diameter of the axial zone 1. Cones havinga length of from about one-third to about one-half of the length ofaxial zone IV have been found satisfactory.

Cone 20 can be supported from support 26 which is adjustable along thelength of axial zone 1 from theexterior of the reactor so as to allowpositioning of the cone independently of oil inlet conduit 6. Hence,cone 20 and make-oil nozzle 8 can be adjustable independently of eachother.

Located downstream of cone 20 is choke 14. This choke conformsexteriorly to the shape of axial zone 1 as defined by wall 16 and isadapted with a centrally located bore 28, and with slots, or openings,27 in its outer wall, these slots being adapted to pass gas from thedownstream side of choke to its upstream side. The bore of the choke, atits minimum diameter, will be of sufficient size to allow the passage ofmake-oil nozzle 8 therethrough.

Any number of slots 27 may be employed in the outer surface of choke 14,it having been found that the number of slots is dependent upon theamount of gas it is desired to recycle back upstream of the choke.Preferably there are from about 2 slots to about 50 slots in the annularwall of the choke. The slots may be any suitable dimension and shape, ithaving been determined that slots are preferably sized in relation tothe production capacity of the reactor, varying in width from about 0.25to about 18 inches, and in depth from about 0.25 to about 5 inches.While these slots generally parallel the bore of the choke which, inturn, parallels the axis of the reactor, slots having a spiralconfiguration can be employed.

The slots generally will lie in the outer wall of the choke and will beformed on three sides by the choke and on the fourth side by wall 16 ofaxial zone 1 as shown in FIG. 2. This view, taken through section 2-2 ofFIG. 1, also shows conduit 6 extending through downstream opening 23 ofcone 20.

Since the purpose of these openings in he choke is to provide passagewayfor some portion of the gases from the downstream side of the choke tothe upstream side of the choke, these openingsmay be formed in anymanner, and may be positioned at any point within the body of the choke.For example, the openings can be formed entirely within the choke wall,the wall of the choke encompassing the opening; or, the openings may beencompassed in part by the choke wall and in part by the wall of theaxial zone. Generally,

passageways formed in any manner, which provides open communication forthe gases from the downstream side of the choke to its upstream side,can be employed. It will be understood that the reactants passed fromthe downstream side of the choke to its upstream side can consist solelyof reactants introduced into the axial zone of the reactor, or of thatcommingled mass of reactants formed when some portion of the reactantsare introduced into the combustion section of the reactor.

The length of the choke has not been found to be critical, lengths ofabout half that of the cone to lengths about equal to the length of thecone have been found to be satisfactory.

The diameter of the bore of the choke will be such that at its maximumdimension, it is less than the diameter of the base 24 of the cone; thatis, the cone can be positioned partially into the bore of the choke withthe result that all flow through the bore of the choke must also passthrough the cone.

lt will be understood that the choke l4, cone 20, and nozzle 8 areindependently positionable. Accordingly, any number of positionalrelationships can be established between these elements, such aswithdrawal of cone 20 remote from choke l4,

In the following two runs, the downstream extremity of the choke waspositioned in alignment with the upstream edge of the combustionchamber. the downstream extremity of the cone being positioned inalignment with the upstream edge of or the seating of cone 20 partiallywithin choke 14. Similarly, 5 the choke. The face of the oil dischargenozzle was positioned nozzle 8 may be recessed into cone 20, forexample. or may in vertical alignment with the downstream edge of thecone, extend into zone 2. in like manner, choke 14 may be posithat is,at a distance of l inches from the upstream edge of tioned at theupstream limit of zone 1 or may be positioned t e mbu ion chamber.Results were as follows:

projecting into zone 2.

in the process of this invention, the introduction of the reactantsthrough conduits 6, 9 and i0 forms a first reaction mass TABLE I withinzone 1. This reaction mass proceeds through zone 1 at a Run Number firstvelocity. As the reaction mass flows into cone 20, through base 24 andthen through choke 14, its velocity will be inc C one and one andcreased the first zone- Doscriptlon choke-unslotted Choke-slotted Thereaction mass formed in zone 1 passes through choke l4 and into thesecond reaction zone 2. Some portion of the gfgg ffial' 8g 3 3greactants from the second reaction zone 2 pass from zone 2goizazllelloegitiort kitrllf :2 1g

x n r, s.c l5 ba ck nto reaction zone 1 through slots 27 of choke 14,the Aflalgas' 0 0 principal portion of reactants from zone 2 passinginto the Combustion air, M s.c.t.h...... 186 186 third reaction zone 3from which carbon black is recovered. ggggfl ggg gg fif g fi 2 Reactantscan be introduced into zone 2 through ports 11 in $1: to oil ratio,s.c.i./ a]--- 653 657 commingling relationship with the first reactionmass, the f g g lf g fi ii 1???? 1%; commingled reaction mass then beingpassed into zone 3 Carbon black properties:

Depending upon the relative position of the choke and cone gg g gg gg ggxxz g; 8% in the first reaction zone, a portion of the first reactionmass, Structure, DBP,cc./100gms 133 146 that is, that portion flowingfirst through the zone, passes at in- .Dismnco upstream "om upstreamedge combustion chamber creased velocity through at least two sectionsof the first reaction zone, while that portion of the first reactionmass 3 bypassing the cone and passing through the choke only, passes atincreased velocity through one section of the first reaction These data}w the operab'l'ty of the pwFess and zone paratus of this invention andshow that at otherwise compara- The process and apparatus of thiinvention h been ble conditions, the use of a slotted choke results inimproved ployed in the production of carbon black and have been foundWelds of cmbon black at comParable photelonfleter to be influential onthe quantity of the carbon black produced, Values of the same type ofblack' results m a Prodt of lush as indicated in the following data.Surface area and h'gher Structure EXAMPLE 1 EXAMPLE ll Two runs weremade on identical Charge Stocks in an axial 40 A second series of runswas conducted as indicated by runs reactor employing, in one run, theslotted choke and cone of 314 and below Runs 3 f 5 p y a cone and a h rFIG. 1, and in the other run, a comparable, but unslotted the Choke ofboth bemg unslotted; 4 p y choke, with cone. Nozzle positions, withreference to the Previously descnbed Slated. choke and conedistanceupstream from the entrance to the combustion The dowllslream exlremllyof Choke was Posltloned chambgr were identicaL alignment with theupstream edge of the combustion chamber,

in both instances, the axial tunnel, in which the choke was thedownstream extremity of the Cone being positioned in i i d was 13 i h idi as was h maximum alignment with the face of the discharge make-oilnozzle. The outside diameter of the choke. The cone was 20 inches long;n r m p ni g o h o n he mak il n zzle its upstream end was 12% inches inoutside diameter and its aligned therewith, were Positioned 6 inches psr m f the downstream end was 4 it; inches in outside diameter, its wallchoke in run 3, 9 inches upstream of the choke in run 4 and i 1thickness being 3/l6 inch. Hence, the inlet area of the cone in hes upream fthe choke in run 5. was 1 l3 square inches and its outlet was l2.6square inches. Except for the slots, the unslotted choke was identicalto the The slotted choke was 10 inches long and had a longitudinalslotted choke, and the cone employed with the unslotted bore orpassageway 8 inches in diameter. It had six slots choke was the same asthat used with the unslotted choke. spaced evenly around its outerperiphery, each slot being 2 in all instances, relative positions ofchoke to combustion inches deep, their total area being 57 squareinches. The unchamber, and nozzles to cone, were as for the previousruns. slotted choke was also 10 inches long. Results were as follows:

TABLE II EmmpieNumbor Cone and Cone and Gone and Descriptionchoke-unslotted choke-slotted choke-unslotted Charge oil rate, gaL/hr352 349 352 Oil inlet temp, F- 400 400 400 Nozzle Location, 1a.- 16 1921 Axial air, M s.c.t.h-. 45 45 45 Axial Gas, M s.c.t.h.- 0 0 0Combustion air, M s.c.t.b.-. 185 185 185 Combustion oxygen, M s.c.t.h-3. 3 3.3 3. 3 Combustion gas, M s.c.1.h 14 14 14 Air to oil ratio,s.c.i.l al 653 669 0153 Conversion, percent to black 44. 3 47.8 47Yield, lb8./g8l 4. l5 4. 49 4. 38

Carbon black properties:

Photelometer 94 88 Surface area, mJ/gm 86 95 87 Structure, DBP, cc./gins 149 Distance upstream from upstream edge 0t combustion chamber.

It will be noted that the nozzle position using the slotted choke wasintermediate those positions employed with the unslotted choke.

The data indicate that at an intermediate position of the nozzle. whenusing a slotted choke and producing black to a comparable photclometervalue, under otherwise comparable conditions. the yield is improved andthe structure and the surface area properties of the black areincreased. These runs also indicate an increase in the overallconversion ofcarbon to black when employing the apparatus and processofthis invention. It is to be noted that, whereas the properties of theblack produced by run 4 at the 19 inch nozzle location would be expectedto have properties intermediate that black produced by runs 3 and 5 inrespect to surface area and structure, the black produced by theapparatus and method of this invention had widely differing properties.

This unexpected result appears to circulation patterns establishedwithin the reactor and most probably to the recirculation of thecombustion gases from the combustion zone upstream into the axial zone.Such recirculation has been shown to occur upstream through the slots ofthe choke and back downstream into the combustion zone through the axialpassageway of the choke. However, it has been determined that the useofa cone, alone, in the absence of a choke of any kind, influences thequality of the carbon black produced.

EXAMPLE lll Two runs were conducted producing carbon black in the samereactor. In one run, neither choke nor cone was used. In the other run,the cone previously described was employed in the absence ofa choke, themake-oil nozzle being positioned at the downstream opening of the cone,as in the previous runs. Results were as follows:

TABLE III Run Number 6 7 No Choke Structure. DBP. cc./l00 g.

These data indicate that the use ofa cone, alone, to direct at least aportion of the axial reaction zone reactants across the make-oil nozzledischarge is effective in changing the structure of the carbon blackproduced. The entrance area of the cone represented, in the above run,was approximately 90 percent of the free flow area of the axial zone,the flow area around the cone at its upstream end representing some 10per cent of the free flow area ofthe axial zone.

It has been determined that the use of a cone is effective when betweenabout 1 percent and about 50 percent of the total flow through the axialzone, preferably about 10 percent to about 40 percent exclusive ofmake-oil, is bypassed around the cone, the balance of the material beingdirected through the cone.

In respect to the dimensions of the choke, the ratio of the area of theaxial bore or passageway of the choke to the area of the downstream, oroutlet, end of the cone has been found to be preferably from about twoto one to about 10 to one.

With reference to the area of the slots of the choke, and in thisrespect to the amount of the gases flowing to the upstream side of thechoke into the axial tunnel from the downstream side of the choke, ithas been found that the total area of the slots to the area of the axialpassageway or bore through the choke preferably ranges from about 0.] toone to about three to one.

In respect to the quantity of materials flowing, the volume of reactantspassing from the second reaction zone upstream through the slots of thechoke into the first reaction zone is about 0.01 to about 0.4 times thetotal volume of reactants flowing from the first reaction zone into thesecond reaction zone through the axial passageway of the choke.

These relationships are advantageously maintained either individually,that is, when employing only one element, or in combination. that is,when employing the choke and cone in combination. Similarly, theseelements are effective in any size reactor when employing anyconventional make oil to produce carbon black under any conventionaloperating conditions.

While the invention has been discussed herein in relation to certainembodiments, it will be appreciated that certain modifications theretocan be made. For example, a choke having a bore varying in diameteralong itslength can be employed, the choke being equipped either withperipheral slots or passageways encompassed by the body of the choke.Similarly, cones having apertured sidewalls can be used. Similarly,means can be employed in conjunction with the cone to effect aspirationof some portion of gas upstream around the edge of the base of the cone,such means being integral with the cone or separate and individuallyadjustable in relation thereto.

Variations such as these, however, are not to be considered as beingoutside of the scope ofthis invention.

What is claimed is:

1. A process for the production of carbon black by the pyrolyticdecomposition of a hydrocarbon feed in a reactor having an axial zone, acombustion zone and a carbon black formation zone in axial alignmentwhich comprises:

a. introducing air and fuel into said axial zone to form a firstmixture;

b. passing into said axial zone and into commingled relationship withsaid first mixture an afterdefined second reactant mass from saidcombustion zone to form a first reactant mass;-

c. passing said first reactant mass through a choke positioned in saidaxial zone at increased velocity;

d. passing said first reactant mass into said combustion zone incommingled relationship with a hydrocarbon feed;

e. introducing through the periphery of said combustion zone and intocommingled relationship with said first reactant mass at least one ofhydrocarbon feed, air and hot combustion gases formed by the oxidationofa fuel to form a second reactant mass;

. passing a portion of said second reactant mass into said axial zone asset forth in step b;

g. passing a portion of said second reactant mass into a carbon blackforming zone under carbon black forming conditions to form carbon black;and,

h. recovering said carbon black;

2. The process as defined in claim 1 in which hydrocarbon feed isintroduced axially into said axial zone and into said first mixture.

3. The process as defined in claim 2 in which a portion of said firstmixture is passed through a truncated cone positioned in said axial zoneupstream of said choke.

4. The process as defined in claim 2 in which said combustion zone has adiameter greater than the diameter of said axial zone and said firstreactant mass upon passing into said combustion zone is expanded fromthe volume of said first reactant mass in said axial zone.

5. The process as defined in claim 2 in which the volume of said secondreactant mass passed into said axial zone from said combustion zone isfrom about 0.01 to about 0.4 of the volume of said first reactant masspassed into said combustion zone.

6. The process as defined in claim 1 in which hydrocarbon feed isintroduced axially into said combustion zone.

t l I i l

2. The process as defined in claim 1 in which hydrocarbon feed isintroduced axially into said axial zone and into said first mixture. 3.The process as defined in claim 2 in which a portion of said firstmixture is passed through a truncated cone positioned in said axial zoneupstream of said choke.
 4. The process as defined in claim 2 in whichsaid combustion zone has a diameter greater than the diameter of saidaxial zone and said first reactant mass upon passing into saidcombustion zone is expanded from the volume of said first reactant massin said axial zone.
 5. The process as defined in claim 2 in which thevolume of said second reactant mass passed into said axial zone fromsaid combustion zone is from about 0.01 to about 0.4 of the volume ofsaid first reactant mass passed into said combustion zone.
 6. Theprocess as defined in claim 1 in which hydrocarbon feed is introducedaxially into said combustion zone.